This invention relates to corn snapping headers of the type used primarily in conjunction with forage harvesters for removing the ears from standing plant stalks and feeding them to the forage harvesting chopping mechanism. More particularly, the invention relates to a header in which standard snapping units from a combine corn harvesting header are disposed in a manner eliminating the need for a lateral consolidating means, such as a cross auger.
Forage harvesters are commonly provided with several different headers for different crops, for example, a hay pickup header, a row crop cutoff header, such as shown in Fritz et al U.S. Pat. No. 4,084,396, which harvests the entire plant at the entrance of the crop passage, and a corn snapping header, which harvests only the ears of corn from the stalk. Ideally, each of the headers would be of the same weight and center of gravity location, so that the forage harvester frame should not have to be overdesigned to accommodate a certain unit. However, previous corn snapping headers have been considerably heavier than row crop cutoff headers and have had their centers of gravity further forward because of the necessity to provide a transverse auger with its supporting structure and drive. Thus, not only was the header heavier, more complex and more expensive but the forage harvester also had to be strengthened at additional expense to carry it.
Previous snapping headers for forage harvesters are essentially a two row version of a combine corn header and have included a pair of laterally adjustable corn snapping units, for example, of the type shown in conjunction with a combine header in Schreiner et al U.S. Pat. No. 3,589,110. In these snapping units, the crop passage, which is defined by the snapping plates, is disposed substantially parallel to the line of travel so that the planted stalk may move rearwardly in the crop passage as the machine moves forwardly, and the corn ears removed therefrom while leaving the remainder of the stalk planted in the field. The ears of corn move rearwardly into a cross auger trough and are moved laterally by the cross auger to the center of the headers and then rearwardly into the forage harvester crop inlet. It has been considered necessary with a snapping plate type snapping unit to maintain the crop passage in line with the path of travel. Disposing the crop passage at an angle to the path of travel would produce an unsatisfactory machine because it would break the stalks and uproot the plants thus increasing the amount of trash and the tendency of the corn header to plug up.
In U.S. Pat. No. 1,936,760 to Hitchcock, a corn picker is shown having two separate crop passages normally parallelly disposed to the path of travel and having independent drives and conveying mechanisms. Although normal row spacing is said to be accomplished by the lateral positioning of the snapping units on a transverse pivot shaft, provision is made for pivoting the snapping units about rear pivots, apparently for adjusting to specific field conditions. The snapping units for the Hitchcock machine, which are shown in Lindgren et al U.S. Pat. No. 1,906,692 were of the old open roll type, which, while being less sensitive to row misalignment and trash, produce much larger shelled corn losses than the fixed snapping plate units in use today. The Hitchcock device was apparently never produced commercially.